After she finished her architectural training, she registered with the Institute of South African Architects in 1927. She was hired by Frederick Man to design the Andros Hotel in 1928 in the Cape Dutch Revival style. This is now known as The Claremont Boutique Hotel. Thereafter she focused as residential architecture and restoration of older buildings. Among her projects were the restoration of buildings on Shortmarket, Longmarket, Rose, and Chiappini Streets in Cape Town's
Bo-Kaap (then called the Malay Quarter) in the 1940s (with Reg de Smit), and creating the South African Cultural History Museum from the former Supreme Court building in the 1960s (the building has housed the
Slave Lodge museum since 1998). She retired from architectural work in 1965. Both projects have since been declared protected historical sites. As a side occupation, Sauer wrote art criticism for
Die Burger newspaper. ==Personal life==